1. Field of the Invention
The present invention relates generally to the technology of operating liquid substance in the vacuum, and more particularly, to a method of operating liquid in the vacuum or low-pressure environment and observing the operation and a device for the operation and the observation.
2. Description of the Related Art
As far as the technology of microscopic observation is concerned, it is known that a user can employ an electron microscope with its high-power magnification to do scientific research of nanometer substances.
A conventional electron microscope works by utilizing an electron beam to probe the substance. It is necessary to utilize the accelerated electron beam by high voltage and to focus the electron beam by using the electromagnetic lenses to do the microscopic observation in a vacuum environment. As shown in FIG. 13, an electron microscope 81 includes a vacuum specimen chamber 82 for receiving a specimen, and an upper pole piece 86 and a lower pole piece 86 both located in the specimen chamber 82 for ensuring precise focus of the electron beam. The distance between the two pole pieces 86 is 1 cm or so. However, any specimen received in the specimen chamber 82 must be a solid, not a fluid such as liquid or gas, to allow observation in such vacuum environment, since a fluid specimen is subject to immediate boiling, volatilization, or the like.
To overcome the above problem and to allow the specimen received in the electron microscope to coexist with a specific gas, an environment chamber for controlling vapor was invented in 1976 (Hui S. W. et al., Journal of Physics E 9, 69, 1976). An electron microscope 91, as shown in FIGS. 14 and 15, includes a heightened specimen chamber 92, a water tank 94 mounted inside the specimen chamber 92, and an environment chamber 96. The environment chamber 96 has two spacers 962 partitioning its center off into a vapor layer 964 and two buffer layers 966 located respectively below and above the vapor layer 964. The water tank 94 has a vent pipe 941 connected with the vapor layer 964 for providing the vapor layer 964 with vapor. The two spacers 962 and top and bottom sidewalls of the environment chamber 96 are parallel to one another, each having an aperture 963. The apertures 963 are coaxial with one another for penetration of the electron beam. The environment chamber 96 further has a specimen tube 967 extending outwards from the vapor layer 964, a specimen holder 968 extending through the specimen tube 967 into the vapor layer 964 from outside, and an O-ring 969 sealing space between the specimen holder 968 and the vapor layer 964 for insulation between the vapor layer 964 and the outside.
However, the aforementioned structure and prior art could merely control the environment chamber 96 to internally keep in the gasiform or vapor environment other than the liquid one.
Another research group for modification of the electron microscope presented an experiment of observation of gasiform, liquid, and solid chemical reactions under the electron microscope in 2002 (Gai P. L., Microscopy & Microanalysis 8, 21, 2002). However, such design has the following drawbacks. Because the liquid specimen is directly exposed to the gasiform environment in the gas chamber covering the space between the two pole pieces, the liquid in the gas chamber will immediately fully volatilize if partial pressure of the vapor fails to reach the saturated pressure, thus requiring supplementary liquid for entry into the specimen target holder in the gas chamber for continuous observation. However, such entry of supplementary liquid will cause serious problems of flow or uneven admixture of new and original specimens to result in inauthenticity of the observation. In addition, the massive volatilized high-pressure vapor or the outside high-pressure gas infused into the gas chamber will fill the space (about or more than 1 cm) between the pole pieces to cause a more serious effect of multiple scattering of the electrons resulting from electrons impinging the gasiform molecules, further disabling successful imaging of the electron beam or experiment of electron diffraction. In addition, the specimen chamber in design fails to effectively control the amount of the infused liquid, causing excessive thickness of the liquid to further disable penetration of the electron beam through the specimen and thus disabling observation and analysis.
Further, it is necessary to disassemble the primary part of the electron microscope before installing the whole system of Gai's design, such that it hardly possible to mass-produce the system.
There was another window-type design/experiment, Daulton T. L. (Daulton T. L. et al., Microscopy Research & Technique 7, 470, 2001). However, such design tends to cause the multiple scattering of the electrons due to thick window film disabling successful imaging of the electron beam or experiment of electron diffraction. Even if the analysis and observation can be done, the resolution is still greatly reduced. Further, if the pressure difference between the window-type specimen and the specimen chamber is too high, the window film is subject to rupture causing immediate volatilization of the liquid inside the specimen chamber and contamination of the vacuum area in the electron microscope, resulting in further malfunction or damage of the electron microscope.
Since the above-mentioned prior art failed to keep a liquid environment in the vacuum or low-pressure environment for operation and observation by the electron microscope, the present invention provides an advanced technology for keeping a liquid environment in the vacuum or low-pressure environment for operation and observation by the electron microscope without alteration of the original design of the electron microscope.